Simulation of the SF6 tracer with the middle atmosphere MAECHAM4 model: Aspects of the large‐scale transport
Simulation of the SF6 tracer with the middle atmosphere MAECHAM4 model: Aspects of the large‐scale transport
复制标题
使用中层大气 MAECHAM4 模型模拟 SF6 示踪剂：大规模输运的各个方面
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
J. Feichter
中科院分区：
文献类型：
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作者：
E. Manzini;J. Feichter
通过分析一个多年模拟，其中包括被动示踪剂，排放量随时间线性增加，旨在代表六氟化硫，SF 6，人为来源的化合物的来源，在大气环流模型中的大规模运输进行评估。分析大规模被动示踪剂输送的一个动机是预期在模拟中使用这种大气环流模型，包括化学模型的主动反馈。结果表明，模拟的SF6浓度随时间的演变和去趋势分布与现有观测值的估计值相当，两者都表现出对流层上部的高值和平流层的低值。模拟与大气环流模式的示踪剂与表面源线性增加的时间和没有汇允许导出的传输时间尺度。从SF 6模拟得出的空气年龄与从观测得出的空气年龄估计值的一般特征是一致的，例如，平流层下部的年龄迅速增加，平流层中部和上部的极地区域年龄较大。平流层年龄分布的纬向和垂直梯度是输送障碍的表现。通过位涡梯度诊断了输运障碍的平均行为。模拟的平流层中低层位涡梯度障碍与欧洲中期天气预报再分析中心的结果相当。
The large-scale transport in a general circulation model is evaluated by analyzing a multiyear simulation that included a passive tracer, with emissions linearly increasing with time, aimed at representing the sources of sulphur hexafluoride, SF 6 , a compound of anthropogenic origin. A motivation to analyze the large-scale passive tracer transport is the expected use of such general circulation models in simulations including active feedbacks with chemical models. It has been found that the time evolution and detrended distribution of the simulated SF 6 concentration are comparable to those estimated by available observations of SF 6 , both displaying high values in the upper troposphere and low values in the stratosphere. The simulation with a general circulation model of a tracer with surface sources linearly increasing in time and no sinks allows derivation of transport timescales. The age of air from the SF 6 simulation is consistent with the general features of age of air estimates from observations, as, for instance, a rapid increase in age in the lower stratosphere and older age in the polar regions of the middle and upper stratosphere. The meridional and vertical gradients that characterize the age distribution in the stratosphere are the manifestation of barriers in transport. The average behavior of the transport barriers is diagnosed by means of the potential vorticity gradient. The simulated barriers in potential vorticity gradient in the lower-middle stratosphere are comparable to that deduced from European Centre for Medium-Range Weather Forecast reanalysis.